Absorption refrigerator



April 1961 KAZU\MI TAMADA ETAL 2,977,775

i ABSORPTION REFRIGERATOR Filed Aug. 6, 1958 5 Sheets-Sheet 1 r 4 7M D April 4, 1961 KAZUMI TAMADA ET AL 2,977,775

ABSORPTION REFRIGERATOR Filed Aug. 6, 1958 5 Sheets-Sheet 2 Fig- 2 if April 1961 VKAZUMI TAMADA ET AL 2,977,775

ABSORPTION REFRIGERATOR 5 Sheets-Sheet 5 Filed Aug. 6, 1958 April 1951 Q KAZUMI TAMADA EI'AL 2,977,775

ABSORPTION REFRIGERATOR Filed Aug. 6, 1958 5 Sheets-Sheet 4 11- 11 I -I i April 1961 KAZUMI TAMADA ETAL 2,977,775

ABSORPTION REFRIGERATOR 5 Sheets-Sheet 5 Filed Aug. 6, 1958 Fig- 8;

of tube type, a heating cylinder and a boiler.

The present invention relates to. improvements. of the.

nited States Paten I entire surface of the vertical portion thereof so as to ingenerator of absorption refrigerators utilizing a. circulating inert gas.

The generator of an absorption refrigerator as described above usually comprises. a liquid circulating pump In the generator of the type as described above, the pump acts e to pump up the strong solution together with the vapor, generated in the. strong solution so as. to discharge them out of the. upper opening of the pump. In such a generator, it is common practice to arrange the pump outside the heating cylinder, or outside the boiler in the case of arrangement of said'boiler around the heating cylinder so that the pump may be parallel'to said boiler and the upper opening ofsaid pump may be communicated with the boiler at a position above-the level of the solution'in the boiler. According to the generator as described above, the liquid circulating pump is scarcely supplied with heat at its vertical portion, and the vapor and liquid ascending through the interior of said vertical portion are deprived ofheat, whereby the pumpv actionis decreased and the heat loss is increased.

For avoiding the above disadvantages, the. followinggenerators have been already proposed.

(I') The generator comprising a pump which is made to passthrough the weak solution in. the boiler heated by the heating cylinder.

(H) The. generator comprising a pump which is arranged outside the heating cylinder so that some heat may be conducted from said cylinder to the pump itself.

In the generators as mentioned in the above types, (I) and (II), the pump action is somewhat improved and heat loss is somewhat reduced in comparison with those ofthe former known generator, but said improvements are not'sufiieient to be usefuliin practice.

Accordingly, an essential object of this invention is to provide improved generators of the type as described above, in which heat loss is remarkably reduced, vaporization of the solution is etfectuated, and the circulating operation of the pump is madevery eflicient.

, We have found that said object andother objects of this'invention can be effectively attained by embracing the vertical portion of the pump. by the heating cylinder to heat directly the pump at the peripheral surface thereof.

According to a preferred construction of this invention, the liquid circulating pump is made to pass uprightly through a heating cylinder so that the level of the strong solution fed from'the reservoir may be above the connecting point of said pump with a liquid heat exchanger which. is disposed between said pump and the reservoir. In embodying this. invention, when a bag-shaped pump chamber for generating vapor bubbles is used, the generator is to be made so thatthe level of the strong solution may be above the point connecting said bagshaped chamber with the liquid circulating pump. According to such: construction, the liquid circulating pump is heated at almost all parts of the outside surface thereof crease the ascending ability of the liquid and vapor,

whereby it is made possible to pump up a sufiicient flow of liquid by use of a pump tube of a relatively large diameter to achieve an efiicient circulation of the liquid. Moreover, the liquid pumping action and. vapor genera.- tion in the pump are increased, whereby the heat load of the. boiler can be reduced. and the. durability of the pump ismade to increase.

While the novel features. which are believedv to be. characteristics: of the. present invention are set forth with particularity in the, appended claim, the present invention itself, however, both as to. its construction and treatment, together with further objects and advantages thereof, may best be. understood. by reference to the following description, taken in connection with the accompanying drawings, in which the samegor similar members are indicated by the same references, andin which:

Fig. 1 is a'schematic side view of an absorption refrigerator, partly sectioned. V

Fig. 2 is a vertical sectional view of a first embodiment of: the. generator 'of this invention.

Fig, 3; is a vertical sectional view of a second embodiment of the generator ofthis invention.

Fig; 4 isa vertical sectional view of a third embodiment of the generator of this invention.-

Fig. 5 is a vertical sectional view of a fourth embodiment of the generator of this invention.

Fig. 6 is a vertical, sectional view of a fifth embodiment of the. generator of this invention.

Fig. 7 is a vertical sectional view of a sixth embodiment of the generator of this invention.

Fig. 8. is a vertical sectional View of a seventh embodiment of the generator of this invention.

Referring to Fig. 1, the absorption refrigerator com prises. a generator A, a rectifier B, a condenser C, a U- shaped tube D, an evaporator E, a heat exchanger F, an absorber G, a liquid reservoir H which is positioned under the absorber G, a carrier tube I, and a liquid heat, exchanger J consisting of a jacket pipe 6 and the pipe 5 passing through said pipe 6. The membersexcept the generator A are almost the same as those in the conven tional absorption refrigerator. Accordingly, descriptionsof'operations and constructions of said members are omitted herein. According to this invention,.the generator A is constructed in such a manner as shown clearly in Fig, 2. The generator A comprises a heating cylinder 2, a bag-shaped chamber 3 arranged around said cylinder to heat the strong solution fed therein from the reservoir H through the pipe 5, a boiler 4 arranged so as to embrace the heating cylinder 2, and a liquid circulating pump 1 of tube type which opens at its lower end in said bag-shaped chamber 3, passes upward through the interior of the heating cylinder 2 and then extends upward out of the upper portion of the heating cylinder 2 so as to protrude from the level I-I of the solution in the boiler 4. The heating cylinder 2 includes a heater which in turn is not shown in the drawings because it can be made as any conventional type, for example as an electric embedded type heater. This heater may be an electric or gas tube of inserted type. In this case, the

tube may be a split type tube.

3 ascends up to the liquid level II-II of the reservoir H, whereby the liquid level in the liquid circulating pump is maintained.

When the heating cylinder 2 is heated by an electric heater orany other heating source, the strong solution in the pump 1 is heated and generates vapor. By the vapor thus generated, the liquid in the pump 1 is pushed up and then discharged out of the upper opening thereof while the liquid is sucked into the bag-shaped chamber 3. Furthermore, the bag-shaped chamber 3 is heated by the heating cylinder 2 so as to generate vapor bubbles, whereby the liquid in the chamber 3 is pushed intothe pump 1 together with said generated bubbles. Thus, the pump 1 drives up the liquid and vapor in said pump, without missing said vapor, into the guide pipe 7 being in communication with the condenser C. In the case, the liquid phase formed in the upper portion of the boiler 4 increases, but the weak solution descends to maintain a predetermined level I-I where the weak solution is charged into the absorber G. The solution entered into the boiler 4 from the pump 1 is entirely deteriorated by vaporization and then supplied to the absorber G through a pipe 8 and the heat exchanger I while being deprived of heat by the strong solution in the pipe 5. The upper portion in the boiler 4 is of lower temperature than the lower portion of the boiler, so that said upper portion forms a rectification layer for rectifying the vapor generated in the lower portion of the boiler. The vapor generated in the boiler 4 reaches the condenser C together with the vapor discharged out of the upper opening of the pump 1 through the guide pipe 7 and rectifier B. The temperature of the strong solution supplied into the bag-shaped chamber 3 through the pipes 5a and 5 from the reservoir H is generally 40 C.-60 C., but said solution is heated at the heat exchanger I by the weak solution of high temperature descending through the jacket pipe 6 of said heat exchanger I. Accordingly, the strong solution is fed into the bag-shaped chamber 3 after being heated to a relatively high temperature. It is preferable to enclose the heat exchanger I together with the generator A in a common, heat insulating casing to reduce the heat loss. Such embodiment of the generator is shown in Fig. 3, in which the various members indicated by the same references are same as those in the embodiment in Fig. 2. In the embodiment in Fig, 3, the generator A and the heat exchanger J are embedded in a heat insulating material 11 and then enclosed in a casing 10, whereby heat loss of the generator A is remarkably reduced.

The generator A in Fig. 2 may be embodied as shown in Figs. 4, 5, 6, 7 or 8. Referring to Figs. 4-8, only the portions differing from the embodiment in Fig. 2 will be described as follows.

In the embodiment in Fig. 4, the bag-shaped chamber 3 is enclosed in the heating cylinder 2 to economize heat and to reduce heat loss from said chamber.

In the embodiment in Fig. 5, the boiler 4 is not constructed so as to embrace the heating cylinder 2, but it is constructed so as to be in contact with the outer surface of the heating cylinder 2 and the upper opening of the heating cylinder 2 is exposed in the atmosphere. According to such construction, the heating cylinder can be used as a gas discharging pipe.

In the embodiment in Fig. 6, the bag-shaped chamber 3 is enclosed in the heating cylinder 2 to economize heat and the boiler 4 is made to be in contactwith the heating cylinder 2. That is to say, the embodiment in Fig. 6 is a combination of the embodiments in Figs. 4 and 5.

In the embodiment in Fig. 7, such a bag-shaped chamber 3 as shown in the other embodiments is not used and the pump tube is connected directly with the heat exchanger J.

In the embodiment in Fig. 8, the bag-shaped chamber 4 cylinder 2. This construction may be used when the bagshaped chamber of a relatively low capacity is allowable.

In embodying this invention, any other form of the heat exchanger such as a U-shape or the like may be used as the heat exchanger I.

Furthermore, when the members are designed so that the position between thepoint P and the level IIII or the portion near said position may be maintained at the maximum temperature of the heating system, the pump action will be effectively improved and the maximum reduction of the heat loss will be obtained. When the maximum temperature portion is below the range between the point P and the level IIII, the heat to be utilized to 1 heat the liquid is reduced, and more particularly the heat supplied to the boiler reduces, whereby the vaporization capacity of the boiler and the efficiency of the generator is lowered. Furthermore, when the maximum temperature portion is below the range between the point P and the level IIII, the heat exchanger I will be overheated in the embodiment in Fig. 3. On the contrary, when the maximum temperature portion is above said range, the pump action is not effective, whereby the efliciency of the generator will be reduced and the rectification action of the vapor in the boiler will be reduced. When an electric heater enclosed in the heating cylinder is used as the heat source, the heater is preferably formed as a split type tube having section of split ring-shape, but may be formed as any other type. In any case, the heater should be designed so as to maintain the range between the point P and thelevel IIII at a maximum temperature.

Thisinvention is not limited within the above-mentioned embodiments, but may be modified in any other constructions without departing from the true idea and spirit of this invention. That is to say, the forms and combination of the boiler, heating cylinder, liquid circulating pump and heat exchanger may be different depending uponthe various conditions such as concentration of the liquid, pressure and the actual constructions of the members. For example, the liquid circulating pump may be passed eccentrically through the heating cylinder without passing through the center line of said cylinder, or the pump tube may be led out of the heating cylinder and then extended upwards after passing through the weak solution of the boiler. These are unimportant variations. It is important to arrange the liquid circulating pump so that the pump may be positively heated from outside for at least its portion which is below the level IIII.

' We claim: In an absorption refrigerator in which a combination of inert and cooling gases and an absorption liquid for absorbing the cooling gas in a strong solution is circulated in a refrigerating cycle, said refrigerator having a generator for circulating the absorption liquid and for separating the cooling gas therefrom, a condenser for condensing the cooling gas to a cooling liquid, an evaporator for evaporatingthe cooling liquid to provide refrigeration, an absorber for returning the cooling gas into the absorption liquid thus forming strong solution, and a reservoir for receiving said strong solution from the absorber, an improved generator comprising in combination; a substantially vertical heating cylinder for circumferential radiant heating, a tubular boiler having upper and lower ends and enclosing the upper portion of said heating cylinder and being heated thereby, said upper end connecting with said condenser for the discharge of cooling gas thereto and the lower end for the discharge of absorption liquid therefrom; a pump tube mounted in said heating cylinder and extending upward through said heating cylinder into the tubular boiler and extending downward through said heating cylinder for receiving the strong solution from said reservoir, and connecting means including preheating means of the strong solution, said connecting means re- 3 is made in contact with the outer surface of the heating spectively connecting the lower end of said pump tube to the reservoir and the lower end of said tubular boiler to said absorber thereby providing paths for said absorption liquid to and from the generator, and said preheating conduit being connected at its respective ends with the bag-shaped chamber and the reservoir respectively and the other conduit being connected at its respective ends with the boiler and the absorberrespectively, said hot absorption liquid as it passes from tubular boiler to absorber, heating the strong solution as it passes from reservoir to the bag-shaped chamber and pump tube; said pump tube being progressively heated by circumferential radiation from the heating cylinder to further vaporize the cooling gas out of solution as the initially vaporized gas carries the liquid from the bag-shaped chamber up the pump tube, said cooling gas being discharged to the condenser and the almost spent absorption liquid being discharged into the tubular boiler and to direct contact with the heating cylinder for effecting vaporization of the remainder of the cooling gas in solution, said cooling gas remaining rising to join the gas discharged from the pump tube, whereby said gas is practically completely separated from said absorption liquid and said gas and absorption liquid are respectively carried by the action of said generator to said rectifier and said absorber.

References Cited in the file of this patent UNITED STATES PATENTS W 

